Leeks are one of those vegetables that need to be cooked before eating as raw leek is very hard to digest. Leeks, like garlic and onions, belong to a vegetable family called the Allium vegetables. Since leeks are related to garlic and onions, they contain many of the same beneficial compounds found in these well-researched, health-promoting vegetables. A high intake of Allium vegetables has been shown to reduce total cholesterol and LDL, or "bad" cholesterol levels, while at the same time raising HDL, or "good" cholesterol levels. The allium family have anti bacterial properties. They are a source of iron, vitamin B6 and folate.